Bell 47G

Full Narrative

On January 11, 2019, about 1440 mountain standard time, a Bell 47G-2 helicopter, N3755Z, collided with terrain while maneuvering near Belen, New Mexico. The pilot and passenger were not injured, and the helicopter was substantially damaged. The helicopter was owned by the pilot and operated under Title 14 Code of Federal Regulations (CFR) Part 91 as a personal flight without a flight plan. Day visual meteorological conditions prevailed for the local flight that departed Belen Regional Airport (BRG), near Belen, New Mexico, about 1400.The pilot stated that shortly before the accident he had maneuvered the helicopter into an out-of-ground effect hover about 50 ft above the ground. The pilot reported that the carburetor heat was not engaged while he flew the helicopter in the hover. The pilot stated that he "got complacent about maintaining main rotor speed" and subsequently observed an unsafe main rotor speed. The pilot lowered the collective control for an immediate landing and engaged the carburetor heat. He attempted to reduce the helicopter's descent rate before impact by increasing the collective control, but the helicopter landed hard in the soft terrain. The main rotor blades subsequently impacted the tail boom and tail rotor. The pilot reported that after impact the engine continued to run at about 1,500 rpm, and that he secured the engine by turning the fuel valve to OFF. The pilot reported no preimpact mechanical anomalies with the helicopter that would have precluded normal operation. The pilot postulated that an insufficient main rotor speed had precluded him from making a normal flare and landing. The pilot stated that the engine might have encountered carburetor icing as he maneuvered the helicopter into the out-of-ground effect hover at a decreased engine power setting, which, in turn, might have contributed to his failure to maintain adequate main rotor speed while hovering.

A postaccident review of available meteorological data established that day visual meteorological conditions prevailed at the accident site. The nearest aviation weather reporting station was located at Belen Regional Airport (BRG), about 3 miles north of the accident site. At 1435, about 5 minutes before the accident, the BRG automated surface observing system reported: wind 310° at 8 knots, 10 miles surface visibility, clear sky, temperature 8°C, dew point 1°C, and an altimeter setting 29.96 inches of mercury.

According to a carburetor icing probability chart contained in FAA Special Airworthiness Information Bulletin CE-09-35, entitled "Carburetor Icing Prevention", the recorded temperature and dew point were in the range of susceptibility for the formation of carburetor icing at all engine power settings.